1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a computer-readable recording medium.
2. Description of the Related Art
In e-mail and the like, pictographic images are often inserted in sentences created. Pictographic images are images of faces in various expressions, animals, symbols, items, and such designed in font sizes typically used in documents and are displayed together with text by a supporting application. As an example, an e-mail function, installed in a cellular phone terminal uses pictographic images of 20 dots high by 20 dots wide. Pictographic images used in a document can provide the document with a wider range of expression, resulting in being widely used.
Japanese Patent Application Laid-open No. 2001-043000 discloses a mail tool that allows a hand-drawn image entered, using a pen-input tablet to be written into an e-mail document being created with e-mail creation software. According to Japanese Patent Application Laid-open No. 2001-043000, a user can send images created by hand-drawing by pasting the images in an e-mail document.
To create eye-friendly pictographic images as intended by the user using a limited number of dots, such as 20 dots high by 20 dots wide described above, requires skill and is very difficult in general. For example, to represent a given shape by a pictographic image, the user needs to decide a color for each dot considering an overall appearance and to appropriately select parts to be omitted.
As an example, as illustrated in (a) of FIG. 27, a grid having the number of cells corresponding to the horizontal and vertical dot sizes of a pictograph is prepared in a certain degree of size (in this example, 400 dots high by 400 dots wide) so as to be easily operated and recognized by the user. The user selects and sets a color for each of the cells of the grid to draw an image to be an original of the pictographic image intended. In (b) of FIG. 27, illustrated is an example of a pictographic image of 20 clots high by 20 dots wide created in such a manner.
In this method, creating a pictograph requires operation on the individual cells, resulting in extremely time consuming. Furthermore, it is difficult to depict a curved line or a straight line having a given angle with a small number of dots, and a part that is necessary to omit may arise in some cases. It is, therefore, very difficult to create a pictographic image of a given shape in a well-balanced form.
Meanwhile, it is conceivable to produce a pictographic image by creating an original image that is large enough to draw easily using continuous curves and lines and reducing the original image thus created to 20 dots high by 20 dots wide, for example. In this case, when a reduction process is simply performed on the image of a large size, the reduced image may look like a faded graphic because necessary lines are dropped out and such, and thus become indistinct.
An example of reduction to one-twentieth of an original image of 400 dots high by 400 dots wide both horizontally and vertically to produce a pictographic image of 20 dots high by 20 dots wide is considered. In this case, for example, a line of less than 20 dots wide in the original image becomes less than one dot wide after being reduced, and this line may in effect disappear by an interpolation process and such during the reduction process.
In Japanese Patent Application Laid-open No. 2001-043000, images created by hand-drawing are written directly to an e-mail document without undergoing a reduction process. As a result, text and images are displayed in uneven sizes. Moreover, when a plurality of images are written in a single e-mail document, in addition to the uneven sizes of the text and the images, the sizes among the images can be also inconsistent.
Therefore, there is a need for solution to reduce visibility degradation in a reduced image the size of which is reduced from that of an original image to fit in a display size.